35、PCI设备驱动简介

PCI(Peripheral Component Interconnect)总线标准是一种将系统外部设备连接起来的总线标准，速度可以达到133MB/s，它是PC中最重要的总线，其他总路线如ISA总线，USB总线等，都挂载在PCI总线上（通过桥接电路）。由Intel推出的一种局部总线，为32位数据地址总线，可以扩展为64位，支持突发读写，及多组外围设备。

在PCI系统中，Host/PCI称为北桥，连接主处理器总线到基础PCI局部总线；PCI-ISA桥称为南桥，连接基础PCI总线到ISA总线。其中南桥通常还含有中断控制器，IDE控制器，USB控制器和DMA控制器等设备。

图示 P412

PCI有三个相互独立的物理地址空间：设备存储器地址空间，I/O地址空间和配置空间。由于PCI支持设备即插即用，所以PCI设备不占用固定的内存地址空间或I/O地址空间，而是可以由操作系统决定其映射的基址。

PCI总线规范定义的配置Hha总长度为256个字节，配置信息按一定的顺序和大小依次存放。根据读取PCI配置空间，可以得到PCI设备的所有资源。[1]中讲述了多种读取PCI配置空间的方法，包括通过最基本的I/O端口操作进行读取，通过DDK提供的函数HalGetBusData,HalSetBusData在NT式驱动中进行读取，在WDM驱动中的读取方法，等。

一般程序所看到的内存指针都是虚拟内存，如果想操作物理内存，必须使用DDK提供的内核函数WRITE_REGISTER_XX,READ_REGISTER_XX系列函数。

MmAllocateContiguousMemory分配连续的物理地址，MmGetPhysicalAddress得到连续的物理内存地址。

#pragma PAGEDCODE
NTSTATUS InitMyPCI(IN PDEVICE_EXTENSION pdx,IN PCM_PARTIAL_RESOURCE_LIST list)
{
    PDEVICE_OBJECT fdo = pdx->fdo;

    ULONG vector;
    KIRQL irql;
    KINTERRUPT_MODE mode;
    KAFFINITY affinity;
    BOOLEAN irqshare;
    BOOLEAN gotinterrupt = FALSE;

    PHYSICAL_ADDRESS portbase;
    BOOLEAN gotport = FALSE;
     
    PCM_PARTIAL_RESOURCE_DESCRIPTOR resource = &list->PartialDescriptors[0];
    ULONG nres = list->Count;
    BOOLEAN IsMem0 = TRUE;
    for (ULONG i = 0; i < nres; ++i, ++resource)
        {                        // for each resource
        switch (resource->Type)
            {                    // switch on resource type
        case CmResourceTypePort:
            portbase = resource->u.Port.Start;
            pdx->nports = resource->u.Port.Length;
            pdx->mappedport = (resource->Flags & CM_RESOURCE_PORT_IO) == 0;
            gotport = TRUE;
            break;

        case CmResourceTypeMemory:
            if (IsMem0) 
            {
                pdx->MemBar0 = (PUCHAR)MmMapIoSpace(resource->u.Memory.Start,
                    resource->u.Memory.Length,
                    MmNonCached);
                pdx->nMem0 = resource->u.Memory.Length;
                IsMem0 = FALSE;
            }else
            {
                pdx->MemBar1 = (PUCHAR)MmMapIoSpace(resource->u.Memory.Start,
                    resource->u.Memory.Length,
                    MmNonCached);
                pdx->nMem1 = resource->u.Memory.Length;
            }

            break;

        case CmResourceTypeInterrupt:
            irql = (KIRQL) resource->u.Interrupt.Level;
            vector = resource->u.Interrupt.Vector;
            affinity = resource->u.Interrupt.Affinity;
            mode = (resource->Flags == CM_RESOURCE_INTERRUPT_LATCHED)
                ? Latched : LevelSensitive;
            irqshare = resource->ShareDisposition == CmResourceShareShared;
            gotinterrupt = TRUE;
            
            break;

        default:
            KdPrint(("Unexpected I/O resource type %d\n", resource->Type));
            break;
            }                    // switch on resource type
        }                        // for each resource

    if (!(TRUE&& gotport&& gotinterrupt    ))
        {
        KdPrint((" Didn't get expected I/O resources\n"));
        return STATUS_DEVICE_CONFIGURATION_ERROR;
        }

    if (pdx->mappedport)
        {                        // map port address for RISC platform
        pdx->portbase = (PUCHAR) MmMapIoSpace(portbase, pdx->nports, MmNonCached);
        if (!pdx->mappedport)
            {
            KdPrint(("Unable to map port range %I64X, length %X\n", portbase, pdx->nports));
            return STATUS_INSUFFICIENT_RESOURCES;
            }
        }                        // map port address for RISC platform
    else
        pdx->portbase = (PUCHAR) portbase.QuadPart;

    NTSTATUS status = IoConnectInterrupt(&pdx->InterruptObject, (PKSERVICE_ROUTINE) OnInterrupt,
        (PVOID) pdx, NULL, vector, irql, irql, LevelSensitive, TRUE, affinity, FALSE);
    if (!NT_SUCCESS(status))
        {
        KdPrint(("IoConnectInterrupt failed - %X\n", status));
        if (pdx->portbase && pdx->mappedport)
            MmUnmapIoSpace(pdx->portbase, pdx->nports);
        pdx->portbase = NULL;
        return status;
        }

#define IMAGE_LENGTH (640*480)
    //申请一段连续物理地址来读取图像
    PHYSICAL_ADDRESS maxAddress;
    maxAddress.u.LowPart = 0xFFFFFFFF;
    maxAddress.u.HighPart = 0;

    pdx->MemForImage = MmAllocateContiguousMemory(IMAGE_LENGTH,maxAddress);

    PHYSICAL_ADDRESS pycialAddressForImage = MmGetPhysicalAddress(pdx->MemForImage);

    WRITE_REGISTER_BUFFER_UCHAR((PUCHAR)pdx->MemBar0+0x10000,
        (PUCHAR)&pycialAddressForImage.u.LowPart,4);

    return STATUS_SUCCESS;    
}

示例代码 P428

参考

[1] Windows 驱动开发技术详解，张帆